Javascript 将新项目添加到对象和don'；t更新js中对象的现有密钥

我有2个对象，我想创建一个函数，在这里我可以传递我的两个对象，该函数应该给出一个新的对象，它可以添加在第二个对象中找到的新项目，但第一个对象上的现有键不应该被更新

例如：-

var a  = {
   name:'luisa kate should remain same',
   cast:'THis will remain as it is.'
}

var b = {
  name:'luisa kate should be not updated object because there is already name in object a ',
  school:'lords light academy should be added in new object'
}

 function update(a, b) {
   var c = {};
   for (var key in a) {
     c[key] = a[key];
   }
   for (var key in b){
     if(key in b){

     }else{
       c[key] = (Array.isArray(a[key])) ? a[key].concat(b[key]) : b[key];  
     }
   } 
   return c
 }
 console.log(update(a,b))

预期产出：-

{
   name:'luisa kate should remain same',
   cast:'THis will remain as it is.'
   school:'lords light academy should be added in new object'
}

---

我玩了很多我的上述更新功能，但我无法解决，请帮助我

我认为您可以使用对象分配

var a  = {
   name:'luisa kate should remain same',
   cast:'THis will remain as it is.'
}

var b = {
  name:'luisa kate should be not updated object because there is already name in object a ',
  school:'lords light academy should be added in new object'
}

c = Object.assign(b, a);
console.log(c);

你也可以试试这个：

var a = { name:'luisa kate should remain same', cast:'THis will remain as it is.' }
var b = { name:'luisa kate should be not updated object because there is already name in object a ', school:'lords light academy should be added in new object' };
var c={}, k;
[a,b].forEach(function(O){
    for(k in O) if(typeof(c[k])=="undefined") c[k]=O[k];
});

console.log(JSON.stringify(c));

此外，如果您需要这两个值（类似于您自己的解决方案）：

for（var-key-in-b）{if（key-in-a）{

？-因为在循环

for（var-key-in-b）{

，显然

（key-in-b）

是正确的

var c={}, k;
[a,b].forEach(function(O){
    for(k in O) if(typeof(c[k])=="undefined") c[k]=O[k]; else c[k]=[c[k],O[k]];
});